Feed regulating and adjusting mechanisms



March 17, 1959 D.'A. GRAEssER FEED REGULATING AND ADJUSTING MECHANIsMs Filed June 6. 1956 Fig 2' INVENTOR.v

David A. Graesser WITNESS y 'ATTORNEY United States Patent Fran REGULATING AND AnJUsrrNG AMis cuaisusMs David A. Graesser, Westport, Conn., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application .lune 6, 1956, Serial N o. 589,611

3 Claims. (Cl. 112-210) This invention relates to improvements in adjusting and reversing devices for the work feeding mechanism of a sewing machine.

It is an object of this invention to provide a means for biasing the feed adjusting and reversing devices toward a predetermined position of adjustment.

It is a further object of this invention to provide a means readily Aaccessible to the machine operator for at will rendering said biasing means effective or ineffective;

With the above and other objects and advantages in view as will hereinafter appear, this invention comprises,l

the devices, combinations and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment in which:

Fig. l represents a vertical cross-sectional view of the standard portion of a conventional sewing machine illus-` trating the regulating and adjusting devices for a conventional drop feed mechanism and having this invention applied thereto;

Fig. 2 represents `an enlarged elevational ,view of an4 exterior portion of the rear wall of the sewing machine' standard of Fig. l including the operator influenced device for at will rendering the biasing means effective or ineffective; and

Fig. 3 represents an enlarged elevational view of an interior portion of the rear wall of the sewing machine standard of Fig. l with the feed adjusting lever in section.

Referring to Fig. l, this invention is illustrated as applied to a conventional sewing machine having a frame including a bed 10, a hollow standard 11 rising from the bed and a bracket arm head (not shown) extending from the standard and overhanging the bed. A main drive shaft 12 which is journaled lengthwise in the bracket arm head and passes through the upper portion of the standard 11, serves in the usual manner to actuate stitch forming instrumentalities in the bracket arm head and beneath the bed 11.

Fast on the main drive shaft 12 is a feed advance eccentric 13 embraced by a block 14 which is slidable in the bifurcated extremity 15 of a pitman 16 extending downwardly through the hollow standard. The pitman 16 is pivoted at its lower extremity on a pin 17 carried ice pin 20 to an anchor link 21 which is pivoted in turn by a pin 22 to an anchor link carrying block 23. The block 23 is journaled on a pin 24 fast in the machine standard. Pivotally carried on a pin 25 secured in the block 23 is one extremity of a connecting link 26 pivoted at its other extremity by means of a pin 27 to a control lever 28. The control lever 28 is secured on a fulcrum pin 29 by means of a set screw 30, the fulcrum pin being disposed horizontally in a split bushing 31 carried in a boss 32 formed in the rear wall of the machine standard. A thumb screw 33 threaded into the boss engages the split bushing and provides for an adjustment of the friction between the split bushing 31 and the fulcrum pin 29. The control lever 28 extends through a vertical slot 34 formed in the front wall of the machine standard and is formed exterorly of the standard with a handgrip portion 35. Secured to the front wall of the standard adacent the vertical slot 34 is an indicia plate 36 which is traversed by a pointer 37 fixed by screws 38 to the control lever.

By means of the control lever 28, the connecting link 26, and the block 23, the sewing machine operator may at will effect changes in the position of the anchor link 21 with respect to the pitman 16, whereby the extent of oscillatory motion imparted to the feed advance rock shaft 19 may -be regulated and the direction of oscillation may be changed to reverse the direction of feed of the work being stitched. Thus, when the anchor link 21 is shifted into substantial alignment with the pitman 17, or more precisely into substantial parallelism withra line joining the pin 17 with the main drive shaft 12, no appreciable motion will be imparted to the rock shaft 19 and no work feeding will occur. When the lever 28 is raised, the pivot pin 22 joining the anchor link 21 to the block 23 will be shifted to the left of the pitman 16 as viewed in Fig. l, and motion will be imparted to the rock shaft 19 to effect work feeding movements in the normally forward direction, that is, in a direction away from the sewing machine operator and from the front to the rear of the sewing machine frame. Similarly, when the lever 28 is depressed and the pivot pin 22 shifted to the right of the pitman 16, the direction of work feeding movements will be reversed and the work will be transported toward the operator.

Threaded into the front wall of the machine standard 11 is a feed length adjusting screw 40 formed with a rounded free extremity 41 extending between angularly arranged abutment surfaces 42 and 43 formed on the anchor link carrying block 23. The surfaces 42 and 43 are arranged on the block such that when the vertex 44 ofthe angle defined therebetween is disposed in alignment with the longitudinal axis .of the feed length adby a rock arm 18 fast on a feed advance rock shaft 19 journaled beneath the bed.

The feed adjusting devices illustrated in Fig. l are adapted for usewith a drop feed mechanism well known in the art in which the feed advance rock shaft 19 is connected to impart feed advance and return movements to a conventional work engaging feed dog (notshown). Since the feed advance eccentric 14 is fast on the main drive shaft 13, the feed movements will occur in timed relation with the operation of the stitch forming instrumentalities. The feed adjusting devices of this invention serve to regulate the extent of feed motion imparted to the feed dog and also serve as a means for reversing the direction of motion of the feed dog.

To this end, the pitman 16 is connected by a pivot justing screw, the feed regulating mechanism will be disposed in a position corresponding to that of zero stitch length. The abutment surfaces 42 and 43 are disposed such that in any position of adjustment, the adjusting screw 40 will limit movement of the block 23 to an equal amount on either side of the zero stitch length position. The maximum stitch length as determined by any position of the adjusting screw 40, therefore, will be the same on both the forward and reverse directions of feed.

One of the most frequent occasions for the use of a feed reversing mechanism in a sewing machine is in the formation of one or two tying or strengthening'stitches at the end of a seam or at a critical wear point along a seam. On these occasions it is advantageous to have a biasing means urging the feed regulating mechanism into a position of adjustment corresponding to a forward direction of feed. With such a biasing means, the operator may accomplish tying stitches simply by shifting the feed adjusting mechanism to the reverse position and then immediately releasing the adjustmg mechanism which will beV returned automatically by the biasing means.

mechanism into the position of adjustment corresponding to the forward direction of feed is in these instances a distinct disadvantage to the machineV operator, smeemanipulation of the work becomes difficult when one.

hand must'be'used' to maintain the feed regulating mechanism in reverse position.

The present inventionl provides a means for the` feed adjusting mechanismA into a forward position-v of adjustment so as to facilitate the formation ofV tying stitches and in addition provides a` means whereby'the machine operator may, at will, render the biasing means ineffective so as to free both of'her` hands for manipulation of the work when a long` seam is to be made in the reverse direction of feed.

Referring to Fig. l, a coil spring, 45 disposed within the machine standard is connected at its lower extremity through an eye dformed' in the feed control lever 28. At its upper extremity, the coil spring 45 embraces a crank pin 47 carried by a crank arm 48 which is fast on a shaft 49 journaled in a bushing 50 fitted into the rear wall of the machine standard above the feed control lever 28 and secured in place on the standard by the screws 51, S4 and 55. The control lever 28, being carried on the horizontal fulcrum pin 29, is constrained to turning movements in a vertical plane. The shaft 49. as illustrated in Fig. l, is journaled in the machine frame above the fulcrum pin 29 and preferably on an axis disposed substantially parallel to the control leverl 28 such that turning movement of the shaft Will effect movement of the crank pin toward and away from the control lever thus to vary the effectiveness of the spring 45. A handle 52 made fast on the shaft 49 exteriorly of the standard by means of a pin 53 is preferably arranged to extend at right angles to the crank arm 48. The fastening screws 54 and 55 project outwardly beyond: the bushing 50 and provide stop members disposed to be engaged by the handle to limit turning movementV thereof to an angle of approximately 180. As illustrated in Figs. 2 and 3, the screws 54 and 55 define the extreme positions of the handle 52 in which extreme positions the handle extends substantially horizontally. The crank arm 43 being disposed at right angles to the handle 52, thus extends substantially vertically in the extreme positions of the handle. As illustrated' in Figs'. l and 2, the crank arm 48 is only slightly inclined from .a vertical upright position when the handle is turned clockwise into an extreme position. In this position the coil spring 45 is distended and is effective to bias the biasingfeed regulating devices into a position correspondingy to a forward direction of feed. In addition, since the crank arm 48 is inclined slightly beyond the vertical upright positiom the distended coil spring will act to bias the handle 52 against the stop screw 55 and thus will prevent accidental movement of the handle 52 into the opposite extreme position. When the handle 52 is turned by the machine operator into its opposite extreme position, as is illustrated in Fig. 3, the rock arm 48 will extend vertically downward and the coil spring willl be collapsed and ineffective to inuence thev feed regulating devices.

The bushing 50 and the parts journaled therein' together with the stop members 54 and 55 carried thereby constitute an organized assembly providing a spring control means which may be applied as a unit to a sewing machine. The construction, ofthis invention thus finds utility not only in the original manufacture of sewing machines butin the modification of existing sewing machines to include a spring control means.

Having. thus described the nature of the invention, what I claim herein is:

l. In a sewing machine having a frame, a work feeding device carried by said frame, actuating mechanism for said work feeding device, and a feedY regulating mechanism operatively connected to said actuating mechanism, means effective at the will of the sewing machine operator for biasing said feed regulating mechanism into a predetermined position of adustment comprising, a coil spring connected at one extremity to said feed regulating mechanism, a member connected to the opposite extremity of said coil spring, and means shiftably supporting said member in said sewing machine frame for movement into a rst extreme position in which said coil spring is collapsed and inoperative and a second extreme, position in which said coil spring is supported in stressed position between said feed regulating mechanism and said member effective to bias the feed regulating mechanism into said predetermined position.

2. In a sewing machine having aframe, a work feeding device carried by said frame, actuating mechanism for said work feeding device, and a feed regulating mechanism operatively connected to said actuating mechanism and including an operator influenced control lever fulcrumed in saidsewing machine frame, means effective at, the will of the sewing machine operator for biasing said control lever into a predetermined position of adjustment comprising, a spring operatively connected at one extremity to said control lever, a shaft journaled for turning movement with respect to said frame, a crank arm extending radially from said shaft, a crank pin carried at the free extremity of said crank arm, said spring operatively connected at its opposite extremity to said crank pin, and a member fast on said shaft constituting an operator influenced handle.

3. In a sewing machine having a frame, a workfeeding device carried by said frame, actuating mechanism for said work feeding device, feed regulating mechanism, `and spring means operatively connected to said feed regulating mechanism, means rendering said spring means effective or ineffectivev at the will of the sewing machine operator to bias said feed regulating mechanism into a predetermined position of adustment, said means comprising, a spring control unit including a bushing secured to said sewing machine frame, a shaft journaled in said bushing, a crank arm extending radially from said shaft, a crank pin carried at the free extremity of said crank arm and arranged in engagement with said spring means, a handle fast on said shaft, and at least one stop member carried by said bushing and disposed in the path of turning movement of said handle to define an extreme position of adjustment of said crank pin.

References Cited in the file of this patent UNITED STATES PATENTS 2,053,757 Woodward et al Sept. 8, 1936 

